lithium batts. not recommended

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hillside
hillside Registered Users Posts: 152 ✭✭
in Solar Beginners Corner #1
My 2 small stand alone systems have been working great for some time now but I need to install 4 new batteries and the Rolls I bought last year for the other system are not available. I'm using Renogy cc's and they do not recommend using lithium batteries. They don't say why...finding batteries on the island is hard enough and the lithium's are more widely available. What's the risk?
8- 235Watt panels, 2 strings in series/parallel, 4 Rolls, 235 AH FLA. batteries, 1800 W.Xantrex pure sine inverter, SRNE ML2440 40Amp Controller &  40 Amp Renogy controller, 24 Volt system. 
5 stand alone PV arrays; 12V gate opener, 24V Dankoff rain water pumping system, 12V Shurflo rain water garden pumping, 12V bathroom lighting and fan.
4- 450 Watt panels with 4 Rolls 235 AH 6 volt batts./ 2-Renogy Tracer 40 Amp controllers/ Xantrex 1800W PSW Inverter.
Honda EU3000W generator for backup.
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  • manzanita2
    manzanita2 Registered Users Posts: 25 ✭✭
    #2
    I'm no expert, but here are my thoughts:
    How old are your charge controllers? Do they have the programming that would allow them to charge LiFePo4 batteries? Lithium batteries do not use the same charging routines as Lead Acid batteries.
    Lithium batteries would not be ideal if your weather gets very hot. I don't remember the high temperature limit. Perhaps about 110 to 115 degrees F. If your temperatures get very cold the batteries often need to be heated before they can accept a charge without damaging them. One manufacturer heats their batteries to 41 degrees F before the system will allow the batteries to be charged.
    So if your charge controllers can charge lithium, or be updated to charge them, and your temperatures are managable, then lithium might work for you. 
    A final thought: 
    Many charge controllers for lithium have communication cables that connect with the electronics in the lithium batteries which allows the electronics in the batteries to communicate the status of the battery. It is possible to charge lithium without the communication cable, but I don't know any details about that.
    Sol-Ark 12, 3 Pytes V5 batteries, currently six REC 420w panels installed. Ten more panels waiting to be installed.
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  • hillside
    hillside Registered Users Posts: 152 ✭✭
    #3
    Thanks...the charge controllers are a couple years old and in the manual they show settings for Sealed Lead Acid, Gel, and Flooded batteries only.
    As for weather, we're in the central Caribbean. It rarely gets much over 92* and below 65*F. Stays in the mid 80's most days.
    It's interesting to see the effect that a slight bit of cloud cover produces more voltage than straight open blazing sun. Panels being black get freakin' hot!
    8- 235Watt panels, 2 strings in series/parallel, 4 Rolls, 235 AH FLA. batteries, 1800 W.Xantrex pure sine inverter, SRNE ML2440 40Amp Controller &  40 Amp Renogy controller, 24 Volt system. 
    5 stand alone PV arrays; 12V gate opener, 24V Dankoff rain water pumping system, 12V Shurflo rain water garden pumping, 12V bathroom lighting and fan.
    4- 450 Watt panels with 4 Rolls 235 AH 6 volt batts./ 2-Renogy Tracer 40 Amp controllers/ Xantrex 1800W PSW Inverter.
    Honda EU3000W generator for backup.
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 7,041 ✭✭✭✭✭✭
    edited July 25 #4
     I have customers with various mixes of batteries. They are all 16 cell lithium iron phosphate and as long as somebody is paying attention you are fine.

    All in parallel,  set 55.2v absorb set for six hours with zero end amps.  You must see the battery state of charge for each bank. When the individual battery state of charge variation gets too large,  run an equalize session getting the battery voltage up to 56 V.

    This is not a set and forget! There must be an adult in the room. I do not use Renogy and so that is your job to make sure it is going to work. 

    This strategy is basically open loop charging.  Closed loop would need matching the battery BMS to the the charge and discharge sources. The BMS in closed loop is networked to the other identical LFP batts internal bms. It is a superior way to use lithium and often very easy to implement.  Good Luck !

    Where in the central Caribbean?  Sailed there alot on my Ketch and alot on Moorings charter boats.

    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • hillside
    hillside Registered Users Posts: 152 ✭✭
    #5
    Puerto Rico.
    Thanks Dave. Just after I made the first post I was able to get new Rolls batteries and everything is back up and running well. Now if the hurricanes stay away...
    8- 235Watt panels, 2 strings in series/parallel, 4 Rolls, 235 AH FLA. batteries, 1800 W.Xantrex pure sine inverter, SRNE ML2440 40Amp Controller &  40 Amp Renogy controller, 24 Volt system. 
    5 stand alone PV arrays; 12V gate opener, 24V Dankoff rain water pumping system, 12V Shurflo rain water garden pumping, 12V bathroom lighting and fan.
    4- 450 Watt panels with 4 Rolls 235 AH 6 volt batts./ 2-Renogy Tracer 40 Amp controllers/ Xantrex 1800W PSW Inverter.
    Honda EU3000W generator for backup.
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  • manzanita2
    manzanita2 Registered Users Posts: 25 ✭✭
    #6
    High winds and flying objects are not good for PV. Hope the weather is nice to you.
    Sol-Ark 12, 3 Pytes V5 batteries, currently six REC 420w panels installed. Ten more panels waiting to be installed.
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